Local Area Network, cable is unplugged...but it isn't

By Nathanisking
May 20, 2009
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  1. Alright here's the story the best way I can explain it...

    About three days ago my desktop computer's internet connection has gone a little wacky. The message: "Local Area Connection-A Network Cable is Unplugged" flashes on and off constantly thus I loose my internet connection for my desktop.

    Here's the thing, while this is happening my wireless network works fine! I don't get it.

    I have a Highspeed Modem (provided by my ISP) a cable going into my Dlink wireless router and another cable going into my computer tower. The light where the 2nd cable is is not on and the WLAN light is flashing intermittently.

    I've already changed all the cables, I've reinstalled all the drivers for the LAN ports on my Motherboard (one is a Yukon Marvell the other is nVidia) no luck. I've also tried the media type switching to every single one ( you know where you go configure advanced options and change the speed/duplex) none of them work.

    Also if I just have my modem and an RJ45 cable into my tower it says I have limited or no connectivity and if I connect my modem with a single RJ45 cable to one of my laptops it says I'm connected but I get "Page Can't be displayed" on both firefox and IE.

    I'm about on the end of my stick here help me out guys!

    Thanks
  2. jobeard

    jobeard TS Ambassador Posts: 13,040   +223

    We run one connection to the router at a time, exclusively {wired vs wireless} -- there's no point to having both at the same time as only ONE will be used anyway (due to the routing tables)

    I hope the router is cabled to the WAN slot on the router and your tower to any LAN slot.
    leave that for now -- you need a connection before those matter anyway
    both of these imply the NIC is not properly configured.
    Let's get the wired connection working first w/o the router and then we'll add it back.

    Enable any firewall you have installed!!!
    Then connect the modem directly to your Tower RJ45 NIC connection.

    First; use and admin account for all this work. get the device manager
    run->devmgmt.msc
    scroll to Network Adapters and expand [+] to see what's installed
    there should be no red or yellow flags; either implies a driver issue
    solve this (if any) before anything else​
    Second;
    use View Network Connections and right click on the Lan connection
    and select Properties
    Scroll to Internet Protocol TCP/IP; click on it and then click the Properties button
    There are two pair of choices; on both use the Obtain IP (DNS) automatically
    click ok to close and click the next OK too​
    Now get a command prompt (run->cmd) and enter ipconfig /all
    you'll get back these (and more)
    Dhcp Enabled. . . . . . . . . . . : Yes
    Autoconfiguration Enabled . . . . : Yes
    IP Address. . . . . . . . . . . . : 192.168.0.4
    Subnet Mask . . . . . . . . . . . : 255.255.255.0
    Default Gateway . . . . . . . . . : 192.168.0.1
    DHCP Server . . . . . . . . . . . : 192.168.0.1
    DNS Servers . . . . . . . . . . . : 208.67.222.222
    208.67.222.220
    Lease Obtained. . . . . . . . . . : Monday, May 18, 2009 7:46:05 AM
    Lease Expires . . . . . . . . . . : Monday, January 18, 2038 8:14:07 PM​
    All that will be different but MUST have these items with IP addresses

    Test the connection with
    1. ping 208.67.222.222
    2. ping www.google.com
    If (1) works, you have a connection to the Internet
    If (2) works, then the browser should find it also by clicking this www.google.com
    If (2) fails, then there's an issue with your DNS, the ISP or some virus.
  3. pasegui

    pasegui Newcomer, in training

    your network adaptor is broken you have to replace it.
  4. jobeard

    jobeard TS Ambassador Posts: 13,040   +223

    That's a premature conclusion that has yet to be proven :(

    If there's "limited connectivity" then the adaptor is running and should only need proper configuration.

    PLEASE refrain from saying must or have to until there's adequate proof.
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